Discriminating Four Geographical Populations of Meretrix meretrix Based on Outline Methods

35, 34, 35, 37 Meretrix meretrixs were collected from the four sea areas of Beihai, Fangchenggang, Haikou and Zhanjiang, respectively, in the South China Sea Coast from October 2013 to March 2014. Shell contours were extracted and digitized by image processing, and converted to binary image, converted elliptic Fourier descriptor(EFDs) by the SHAPE. The EFDs were then identified by using principal component analysis(PCA) and gradual discrimination analysis(GDA). The result indicated that the three principal components(PCs) accounted for 80.67% of the total variation, in which the first PC accounted for 49.72%. The GDA of EFDs indicated that exactitude distinguishing accuracy of four geographical populations(GPs) were among 65.7%- 94.6%, and the cross validation were among 60.0%- 94.6%. The lowest accuracy of the four areas appeared when discriminating the population in Haikou while the highest appeared when discriminating the population in Zhanjiang. The average exactitude distinguishing accuracy is 78%. And the cross validation were among 60.0%- 94.6%. The lowest and the highest distinguishing accuracy appeared when discriminating populations in Haikou and Zhanjiang respectively. The average exactitude distinguishing accuracy is 74.5%. It indicated that outline method was effective in discriminating Meretrix meretrix from the four sea areas.